1. Field of the Invention
The invention relates to a piezoelectrically controllable microfluid actor system.
2. Description of the Prior Art
EP 1 150 105 A2 has made known gas-cushioned microproportioning systems for proportioning liquid volumes in the microlitre and sub-microlitre ranges. Such systems have a liquid reservoir with a storage space for the liquid to be proportioned, the borderline of which is broken through by an outwardly leading liquid passage and a gas passage. They further have a gas displacement system with a micropump for pumping a gas, and a communication with the gas passage. In addition, they have a proportioning control in an active communication with the micro-pump to produce a negative pressure or positive pressure by actuating the micro-pump and applying the negative pressure or positive pressure to the liquid reservoir to receive a liquid in the storage space through the liquid passage or to deliver it therefrom.
Microvalves and micropumps are required to implement such an aircushioned micropipette. The microvalves and micropumps currently available involve relatively great expenditure and, hence, are costly and not particularly suited for an economical use in a series product.
EP 0 134 614 A1 has made known a micropump which comprises at least two valves and at least one displacement chamber wherein the valves and the displacement chamber are piezoelectrically controllable.
The valves and displacement chamber are of the same shape and are connected in series in a duct and can be functionally controlled so as to achieve a peristaltic displacement of the fluid to be pumped through the duct.
The valves and the displacement chamber comprise a silicon chip including channels which are worked in and to the flat upper side of which a glass plate is firmly adhered which, in turn, carries a piezoelectric chip. If a voltage is applied to the piezoelectric chip the glass plate may be bulged away from the silicon chip so as to assume a wave shape in cross-section. As a result, a passage closed by the glass plate will be opened between various channels in the silicon chip, thus making the element passable.
When in a non-deflected condition, the glass plate flatly rests on the silicon chip except for the areas located over the orifices of the channels. Since the piezoceramic element and the underlying support area of the silicon chip are of a similar size the planar compression and, hence, the tightness of the channel blocking devices is relatively low. Moreover, in this arrangement, the glass plate allows to be deflected comparatively little from the silicon chip by controlling the piezoceramic element as compared to undergoing a deflection towards the silicon chip which, however, is impossible in this construction in a non-deflected condition. Also, a consequence of the wave-shaped deflection is that only a very narrow passage is released between the channels.
The production of such microchips requires a large manufacturing expenditure as is common in the semiconductor technology because of a multiplicity of different production steps. Add to this that the substrate materials, specifically silicon, are relatively costly although it is a mass production article.
Accordingly, it is the object of the invention to provide piezoelectrically controllable microfluid actor system (hereinafter also referred to as a “microfluid actor system”) which can be manufactured at a relatively low expenditure and features an improved diaphragm operation.